Sensors are all around us. Sensors are transducers, in that they convert one form of energy into another. For example, widely available electrochemical sensor-based Carbon Monoxide (CO) detectors are installed in many homes and are used to detect the presence of CO as a result of incomplete combustion. Those sensors precisely measure current through a test cell. The current corresponds to CO level and an alarm is activated accordingly.
Advances in sensor miniaturization through microelectromechanical systems (MEMS), micromachining, photolithography and other miniaturization improvements have put sensors and detectors into places such as automotive brake shoes and bearing races that just a few short years ago were not technically or economically sensible.
Providing power to sensors in portable, moveable and out of the way places has significantly limited sensor use. Methods of extending battery or other on-board power supplies in order to extend a sensor system service life have focused mainly on improved battery technology and reducing system power requirements. To a lesser extent, methods of energy harvesting, such as piezoelectric vibration energy harvesting, have helped extend service life but remain costly to implement.
Business and home network administrators are increasingly looking to wireless networking technology to allow rapid and cost-effective changes to work space layout, network configuration and network capacity by deploying wireless networks that are easy to use, install and maintain, all without compromising system performance or security. Low range wireless networking protocols, such as but not limited to, 802.11x protocol, WI-FI wireless networking technology, Ultra-Wideband (UWB), Wireless USB (WUSB), BLUETOOTH wireless networking protocol, ZIGBEE wireless open standard technology and the like, facilitate communication between compatible wireless devices. Those wireless communication technologies have been applied to sensors.
Sensors have been used to identify or track persons in a building. Motion sensors have been used to detect the presence of a person, but are not effective in identifying the person. Fingerprint sensors and retina scanners have been used in security systems to identify persons, but those sensors require active participation by the identified person. Similarly, face and voice recognition software has been used to identify persons, but those techniques also require the active participation by the subject to produce reliable identification. Key fobs and ID cards have been used to identify persons in a building, but those devices must be carried by persons for the purpose of being identified by the system.
It would therefore be desirable to provide systems and methods for identifying and tracking persons within a building, and taking actions based on that identification, without requiring the persons to take affirmative measures to identify themselves to the system. To the inventors' knowledge, no such system or method currently exists.